Remember that enabling TV out mode changes the pinout of the phone.
In "normal" mode with a Nokia control adapter in sound is not correct.
In TV out mode with a Nokia control adapter sound is correct.
In neither case do the Nokia buttons do anything - Play/pause, stop, fwd, rwd, vol+, vol-.
I'm sure the phone is only Nokia compatible when TV out is enabled. In this mode we don't know if..
1) The hardware of the phone can receive a signal from the buttons.
2) The firmware of the phone allows this to be passed to the software.
3) Software can use this input for media players.
Outside of Nokia mode, I don't know the answer to the pinouts.
Of the three pinout links you posted... http://pinoutsguide.com/HeadsetsHead...t_pinout.shtml
seems to be verified. There are three posts saying it's incorrect, but they simply say that the left and right channels are reversed. It's implied from that then that the other aspects are correct.
I think since we're no further forward it wouldn't be a total waste for me to go ahead and get one of the iPhone control adapters off eBay and see what the result is?